Abstract
We present the results of a series of dc I - V measurements ontwo groups of Bi-2223 supercoonducting tapes in varying magnetic field with various field orientations with respect to the broad face of the tapes. One group of the samples consist of superconducting tapes with Ag-sheath of differents hardness and the other group consist of tapes with different oxide additives in the cores. It is shown in the case with parallel and perpendicular field orientations that Jc(B) increases with increasing hardness while Jc(B) is reduced with the addition of oxides in the core. The results of measurements with respect to various field orientations at certain field stengths (0.1 and 0.5 T) exhibits similar trend of Jc(teta) variation with respect to sheath and core treatments, attaining different maximum values of Jc at around the parallel field orientaion.